Some people have abilities but we won't know based on the info you gave. However, feel free to take a look at some of the articles on this site on the basics and see how you feel about them.
I also don't agree with the "alternate genders every other generation" bit. Everyone has the ability to do magic if they so desire with practice and effort. I am not doubting that you may have some innate natural ability, however you need to explore them to help discover what they might be.
You can possibly try to question your grandfather some more or other relatives about these as you do your research.